From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH] net: fix napi_reuse_skb() skb reserve Date: Wed, 21 Mar 2012 09:58:03 -0700 Message-ID: <1332349083.5330.49.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev To: David Miller , Herbert Xu Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:47338 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753315Ab2CUQ6G (ORCPT ); Wed, 21 Mar 2012 12:58:06 -0400 Received: by dajr28 with SMTP id r28so1828909daj.19 for ; Wed, 21 Mar 2012 09:58:06 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: napi->skb is allocated in napi_get_frags() using netdev_alloc_skb_ip_align(), with a reserve of NET_SKB_PAD + NET_IP_ALIGN bytes. However, when such skb is recycled in napi_reuse_skb(), it ends with a reserve of NET_IP_ALIGN which is suboptimal. Signed-off-by: Eric Dumazet Cc: Herbert Xu --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 0f3eb7d..452db70 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3560,7 +3560,8 @@ EXPORT_SYMBOL(napi_gro_receive); static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb) { __skb_pull(skb, skb_headlen(skb)); - skb_reserve(skb, NET_IP_ALIGN - skb_headroom(skb)); + /* restore the reserve we had after netdev_alloc_skb_ip_align() */ + skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN - skb_headroom(skb)); skb->vlan_tci = 0; skb->dev = napi->dev; skb->skb_iif = 0;